Practicals Flashcards
(27 cards)
What is the aim of the microscope practical?
To measure the size of cells using a microscope.
What is the key method in the microscope practical?
Prepare a slide, view at different magnifications, calibrate using a micrometer, calculate actual size.
Why do we calibrate the microscope?
To compare image size with actual size and ensure accurate measurement.
What is the aim of the beetroot practical?
To investigate how temperature or ethanol affects membrane permeability.
What is the key method in the beetroot practical?
Cut beetroot, place in solutions, measure absorbance with colorimeter.
What does more pigment leakage mean?
It means increased membrane permeability.
What is the aim of the enzyme practical?
To investigate how pH or temperature affects enzyme activity.
What is the key method in the enzyme practical?
Mix starch and amylase, use iodine to test at intervals until no colour change.
Why does iodine colour disappear?
Because amylase breaks down starch, stopping the blue-black reaction.
What is the aim of the diffusion agar block practical?
To model diffusion and compare surface area:volume ratio.
What is the key method in the diffusion practical?
Place indicator-stained agar blocks in acid and time colour fading.
Why do smaller blocks lose colour faster?
They have a higher surface area:volume ratio, so diffusion is quicker.
What is the aim of the osmosis practical?
To find the water potential of plant cells.
What is the key method in the osmosis practical?
Weigh tissue before/after soaking in sucrose solutions, calculate % change.
What does no change in mass suggest?
That the solution is isotonic to the tissue (same water potential).
What is the aim of the antimicrobial practical?
To test how antibiotics/antiseptics affect bacteria.
What is the key method in the antimicrobial practical?
Spread bacteria, place discs, incubate, measure inhibition zones.
What do large inhibition zones mean?
More effective antimicrobial activity.
What is the aim of the tropism practical?
To observe how plants grow in response to light or gravity.
What is the key method in the tropism practical?
Grow seedlings in different orientations/light conditions and observe growth direction.
What hormone causes phototropism and geotropism?
Auxin, which redistributes in the plant to cause bending.
What is the aim of the respiration practical?
To measure how conditions affect respiration rate in yeast.
What is the key method in the respiration practical?
Mix yeast with glucose, measure CO₂ with a respirometer/gas syringe.
What does more CO₂ production mean?
A higher respiration rate.
